1. Field of the Invention
The present invention pertains to a method and apparatus for treating congestive heart disease and related valvular dysfunction. More particularly, the present invention is directed to an apparatus and method for delivery of a cardiac constraint jacket to a heart suffering from the effects of congestive heart disease.
2. Description of the Prior Art
Congestive heart disease is a progressive and debilitating illness. A progressive enlargement of the heart characterizes the disease.
As the heart enlarges, the heart is performing an increasing amount of work in order to pump blood each heartbeat. In time, the heart becomes so enlarged the heart cannot adequately supply blood. An afflicted patient is fatigued, unable to perform even simple exerting tasks and experiences pain and discomfort. Further, as the heart enlarges, the internal heart valves cannot adequately close. This impairs the function of the valves and further reduces the heart""s ability to supply blood.
Causes of congestive heart disease are not fully known. In certain instances, congestive heart disease may result from viral infections. In such cases, the heart may enlarge to such an extent that the adverse consequences of heart enlargement continue after the viral infection has passed and the disease continues its progressively debilitating course.
Congestive heart failure has an enormous societal impact. In the United States alone, about five million people suffer from the disease (Classes I through IV combined). Alarmingly, congestive heart failure is one of the most rapidly accelerating diseases (about 400,000 new patients in the United States each year). Economic costs of the disease have been estimated at $38 billion annually.
Not surprising, substantial effort has been made to find treatments for congestive heart disease. Recently, a new surgical procedure has been developed. Referred to as the Batista procedure, the surgical technique includes dissecting and removing portions of the heart in order to reduce heart volume. This is a radical new and experimental procedure subject to substantial controversy. Furthermore, the procedure is highly invasive, risky and expensive and commonly includes other expensive procedures (such as a concurrent heart valve replacement).
Clearly, there is a need for alternative treatments applicable to both early and later stages of the disease to either stop the progressive nature of the disease or more drastically slow the progressive nature of congestive heart disease. Unfortunately, currently developed options are experimental, costly and problematic.
Cardiomyoplasty is a recently developed treatment for earlier stage congestive heart disease. In this procedure, the latissimus dorsi muscle (taken from the patient""s shoulder) is wrapped around the heart and chronically paced synchronously with ventricular systole. Pacing of the muscle results in muscle contraction to assist the contraction of the heart during systole.
Commonly assigned U.S. Pat. No. 5,702,343 to Alferness dated Dec. 30, 1997 teaches a jacket to constrain cardiac expansion during diastole. Also, PCT International Publication No. WO 98/29401 published Jul. 9, 1998 teaches a cardiac constraint in the form of surfaces on opposite sides of the heart with the surfaces joined together by a cable through the heart or by an external constraint. U.S. Pat. No. 5,800,528 dated Sep. 1, 1998 teaches a passive girdle to surround a heart. German utility model DE 295 17 393 describes a non-expansible heart pouch. PCT International Publication No. WO 98/58598 published Dec. 30, 1998 describes a cardiac pouch with an elastic limit.
A cardiac constraint device can be placed on an enlarged heart and fitted snug during diastole. For example, a knit jacket device can be loosely slipped on the heart. After such placement, the material of the jacket can be gathered to adjust the device to a desired tension. The gathered material can be sutured or otherwise fixed to maintain the tensioning. The heart may be pre-shrunk prior to placement of the device or the device may be fitted on the heart without pre-shrinking the heart. The device is adjusted to a snug fit on the heart during diastole.
The process of placing and fitting the constraint device on the heart often requires a certain amount of direct handling and manipulation of the heart. Excessive manipulation is undesirable since the heart may respond by fibrillating requiring the surgeon to exercise defibrillating procedures or therapies. Additionally, placing the constraint device on the heart is often time consuming and technically difficult.
The present invention is directed to reducing the amount of direct handling of the heart, to reducing the time required to place and fit the constraint jacket on the heart, and to reducing the technical complications required in placing and fitting the jacket on the heart.
According to a preferred embodiment of the present invention, a method and apparatus are disclosed for treating congestive heart disease and related cardiac complications such as valvular disorders. A cardiac constraint jacket is formed of flexible material defining a volume between an open upper end and a lower end. The jacket is dimensioned for an apex of a patient""s heart to be inserted into the volume through the open upper end and for the jacket to be slipped over the heart. A delivery device is used in placing the jacket on the heart.
In one embodiment, the delivery apparatus includes a handle and a band. The band has a first end fastened to the handle and a second end releasably fastened to the handle. The cardiac constraint jacket has a receiving member or other engagement structure to be threaded on the band via the second end of the band for subsequent delivery and positioning of the cardiac constraint jacket on the heart.
In another embodiment, the delivery apparatus includes a handle having a releasable end cap and a band. The band has a first end fastened to the releasable end cap and a second end releasably fastened to the handle. The cardiac constraint jacket has a receiving member or other engagement structure to be threaded on the band via the second end of the band for subsequent delivery and positioning of the cardiac constraint jacket on the heart. The releasable end cap of the handle can be used to limit band recoil during the removal of the band from the cardiac constraint jacket.
The present invention is also a method for constraining a heart undergoing congestive heart disease. The method includes the steps of obtaining a cardiac constraint jacket, obtaining a delivery apparatus having a handle and band, securing the cardiac constraint jacket to the delivery apparatus, positioning the cardiac constraint jacket on the heart using the delivery apparatus and removing the delivery apparatus from the cardiac constraint jacket.
These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings.